From Austrians to Nazis to Soviets, this historic Budapest fortress has a history as complex as the city itself.

The last Victorian market in Belfast.

These engineering masterpieces are a dominant feature of the Belfast skyline.

It was once nicknamed "the most bombed hotel in Europe."

These barriers stand as stark reminders of Northern Ireland's troubled past.

A museum marks and documents the site of the Titanic's launch.

Northern Ireland's Brobdingnagian stepping stones.

Originally built to monitor fishing, this Victorian tower now educates visitors about the local salmon industry.

The chaotic studio of one of the 20th century's most important artists has been preserved down to the dust.

Dublin's most modern, visually spectacular bridge is modeled after Ireland's national emblem.

A stunning Victorian abbey and walled garden on a lakefront.

This modest plaza in Moneygall, Ireland has cashed in on its distant connection to the U.S. president.

The modern birthplace of Irish freedom.

A hugely vast Irish landscape of barren rock that stretches for miles.

Amidst the bustling streets of Dublin, there is a hushed garden that is dedicated to "All those who gave their lives in the cause of Irish Freedom."

A moody and picturesque riverside ruin overgrown with vegetation.

The gorgeous library at Trinity College is home to remarkable treasures of Irish identity.

A fascinating insight into daily life in the Eastern Bloc.

A museum dedicated to the history of a terrifying secret police is now held in their former headquarters.

The largest free-standing aquarium in the world resides in a hotel lobby in Berlin.

On the Spree bank, discover one of the last reminders of a symbolic wall that divided, and was torn down by the people.

Uh, pardon me, ma'am, but I couldn't help noticing that there's a Columbo statue in the middle of Budapest.

A museum in the childhood house of a medical pioneer.

A trail of iron footwear stands as a monument to the thousands executed along this riverbank during WWII.